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Addendum to my review of the RDF Based semantics (ACTION-316)

From: Ivan Herman <ivan@w3.org>
Date: Wed, 01 Apr 2009 13:03:58 +0200
Message-ID: <49D34A1E.5090008@w3.org>
To: Michael Schneider <schneid@fzi.de>
CC: W3C OWL Working Group <public-owl-wg@w3.org>

I have also gone through Appendix 7, ie, the correspondence theorem. I
cannot claim to have checked all RDF/Direct semantic condition pairs:-)
but at least I understand what happens in the theorem and its proof
based on the text and I did not find any issue...

My few (and purely editorial) comments are below




This is not strictly on Appendix 7, but is clearly related:

Section 5, notes on the semantic conditions, first paragraph:

"On the other hand, the RDF encodings of OWL 2 descriptions (Section
3.2.4 of [OWL 2 RDF Mapping] and Sections 6 - 8 of [OWL 2
Specification]), such as property restrictions,"

In both the mapping and the syntax document the term 'expressions' is
used and not 'descriptions'. For a better cross reference, the word
'expressions' should be used here, too.


Comments on Appendix 7 itself

Stylistic issues:

it may make the proof easier to read if some notations are defined
upfront; that would avoid repeating them in the statements and the
proofs. I am thinking of:

  - G is an OWL DL ontology in Graph form and F(G) is its FS
representation, meeting the restriction for DL and that results on the
reverse mapping
  - D is a datype for OWL FUll, and F(D) its Direct Semantic version.
Actually, as an abuse of notation I do not think it would lead to any
misunderstandings if F(D) was dropped in the sense that it should be
made it clear in the introduction that the there is such thing as F(D)
(as defined now) but then say that in the remaining of the section we
use the same symbold with the understanding that Direct Semantics is
meant in conjunction with F(D)

These terms are repeated all over the place (which is, of course,
mathematically correct) but makes the reading of the text fairly difficult.


Point "C", in the balancing lemma proof, first bulleted item:

"The removal of annotations by (a) and deprecation triples by (b) from
G2*, as well as the replacement of the ontology header of G2* by (c)
also do not hurt any syntactic restrictions"


"The removal of annotations by (a) and deprecation triples by (b) from
G2*, as well as the replacement of the ontology header of G2* by (c) do
not hurt any syntactic restrictions either"


Proof of the Theorem, paragraph starting with "G1 and G2 are OWL 2 DL
ontologies in RDF graph"

"From this follows that the same literals..."


"This means that the same literals...


Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
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Received on Wednesday, 1 April 2009 11:04:33 UTC

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